Version July 2025
INTRODUCTION —
Constipation is the most common digestive complaint in the general population. It is associated with reduced quality of life and substantial economic costs [1-4].
The etiology and evaluation of chronic constipation will be reviewed here. The recommendations in this topic are largely consistent with guidelines from the American Gastroenterological Association (AGA) and American Society for Gastrointestinal Endoscopy (ASGE) [5,6].
The management of chronic constipation is discussed separately. (See "Management of chronic constipation in adults" and "Management of persistent unresponsive constipation in adults".)
DEFINITION —
Constipation is a symptom-based disorder without standardized diagnostic criteria. Symptoms may include hard stools, excessive straining, infrequent bowel movements (<3 per week), a sense of incomplete evacuation, or the use of manual maneuvers to facilitate defecation. "Chronic" refers to symptoms lasting at least three months.
EPIDEMIOLOGY AND RISK FACTORS —
The estimated prevalence of chronic constipation in North America is 12 to 19 percent [7,8]. Chronic constipation appears to disproportionately affect females and older individuals. In one meta-analysis, the pooled prevalence of chronic constipation in females was almost twofold higher than that in males (17.4 versus 9.2 percent, odds ratio [OR] 2.2, 95% CI 1.87-2.62) [8]. In patients 65 years of age and older, approximately 26 percent of males and 34 percent of females have symptoms of constipation [9,10]. In older adults, constipation appears to correlate with decreased caloric intake but not with either fluid or fiber intake [11-13].
Additional risk factors for constipation include physical inactivity, lower income, and poor education [7,9-15].
ETIOLOGY AND PATHOGENESIS
Approach to classification — Constipation may be secondary to other health conditions or medications or due to primary colorectal dysfunction (ie, chronic idiopathic constipation); it is often multifactorial. When evaluating a patient with constipation, it is helpful to first consider secondary etiologies. In patients without secondary etiologies, consider a diagnosis of irritable bowel syndrome (IBS) if the patient describes associated abdominal pain or discomfort. Once this is ruled out, a diagnosis of chronic idiopathic constipation can be made.
Chronic idiopathic constipation includes defecatory dysfunction, slow transit constipation, and normal transit constipation (ie, functional constipation).
It is important to note that these are not distinct, mutually exclusive categories, but rather a useful framework with which to approach the evaluation of constipation (eg, a patient with a rectocele may have secondary constipation but also fall into the categories of defecatory dysfunction and slow transit constipation).
Secondary chronic constipation — In patients presenting with constipation, we first consider secondary etiologies of their symptoms (table 1).
●Neurogenic disorders – Diseases of the central and peripheral nervous systems are often associated with constipation. Colonic and anorectal motor functions are coordinated by enteric, sympathetic, and parasympathetic nerves, and any disorder that impairs these systems can lead to constipation [16]. This includes:
•Spinal cord injury and disease – The distal colon receives parasympathetic innervation from the sacral nerves that pass through the pelvis and enter the bowel wall in the rectum. Transection of these nerves or lesions in the cauda equina may produce constipation associated with hypomotility, colonic dilatation, decreased rectal tone and sensation, stasis of the distal colon, and impaired defecation. Similar findings may occur with injury to the lumbosacral spine, with a meningomyelocele, and following low spinal anesthesia. Constipation may also be a result of high spinal cord damage. However, in contrast to lower cord damage, colonic reflexes are intact, and defecation can often be triggered by digital stimulation of the anal canal. (See "Chronic complications of spinal cord injury and disease", section on 'Gastrointestinal complications'.)
•Parkinson disease – Constipation in Parkinson disease is likely due to autonomic dysfunction; it is a common symptom and may precede motor symptoms in some patients [17,18]. The risk of constipation in patients with Parkinson disease may be further increased by medication side effects and loss of physical mobility [19]. (See "Clinical manifestations of Parkinson disease".)
•Multiple sclerosis – Constipation is the most common bowel disorder associated with multiple sclerosis. Patients with advanced multiple sclerosis who have severe constipation demonstrate absent colonic motor responses after eating a meal and show anorectal sensory dysfunction (such as rectal hyposensitivity) or motor dysfunction (such as dyssynergic defecation), possibly from lumbar and sacral plexus nerve damage [20]. The high prevalence of constipation in multiple sclerosis may be worsened by physical inactivity or the use of medications with constipating side effects [21]. (See "Clinical presentation, course, and prognosis of multiple sclerosis in adults".)
•Hirschsprung disease – Hirschsprung disease is a congenital disorder characterized by obstipation from birth and colonic dilatation proximal to a spastic, nonrelaxing, and nonpropulsive segment of distal bowel. It occurs due to absent intramural ganglion cells of the submucosal and myenteric plexuses, which occurs as a result of arrest of the caudal migration of neural crest cells during embryonic development. Although Hirschsprung disease is usually detected in early childhood, patients with less severe disease are occasionally diagnosed in adulthood. (See "Congenital aganglionic megacolon (Hirschsprung disease)".)
•Chagas disease – Chagas disease is caused by the protozoan parasite Trypanosoma cruzi; the major manifestations are cardiomyopathy and gastrointestinal disease (eg, achalasia). Constipation is due to damage to the neurons of the enteric nervous system. (See "Chagas gastrointestinal disease".)
•Chronic intestinal pseudo-obstruction – The pathogenesis of chronic intestinal pseudo-obstruction is multifactorial and can include abnormalities of the enteric nervous system, smooth muscle of the gastrointestinal tract, or the interstitial cells of Cajal. These abnormalities can be secondary to another medical condition (eg, diabetes mellitus, systemic lupus erythematosus), or may be idiopathic. (See "Chronic intestinal pseudo-obstruction: Etiology, clinical manifestations, and diagnosis".)
●Endocrine and metabolic conditions – Endocrine and metabolic conditions that can cause or contribute to constipation include hypercalcemia, hypokalemia, diabetes mellitus, and hypothyroidism.
•Hypercalcemia – Hypercalcemia may cause constipation through decreased smooth muscle tone or abnormal autonomic function. Constipation is usually related to severe hypercalcemia, although can sometimes be seen even in mild hypercalcemia. (See "Clinical manifestations of hypercalcemia".)
•Hypokalemia – Hypokalemia may cause constipation due to impairments in smooth muscle contraction and colonic motility.
•Diabetes mellitus – Constipation in diabetes mellitus is multifactorial and likely at least in part due to autonomic neuropathy of the enteric nervous system.
•Hypothyroidism – Constipation is one of the most common symptoms of hypothyroidism; the mechanism is through decreased colonic motility. (See "Clinical manifestations of hypothyroidism".)
●Obstructive colorectal conditions – Obstructing lesions of the gastrointestinal tract may cause constipation. Examples include colorectal cancer, rectoceles, and strictures.
●Medications – Constipation may also be due to medication side effects (table 1). Medications that frequently cause constipation include opioids, ondansetron, and iron supplements. Additional agents that can cause constipation include anticholinergics (eg, tricyclic antidepressants), antihypertensive agents (eg, calcium channel blockers), and vinca alkaloids (eg vincristine).
●Other – Additional conditions that can cause or contribute to constipation include myopathies (eg, systemic sclerosis, myotonic dystrophy, amyloidosis), celiac disease, and anorexia nervosa. Pregnancy is also associated with constipation.
Irritable bowel syndrome with constipation — IBS is a functional disorder of brain-gut interaction characterized by the presence of recurrent abdominal pain associated with altered defecation, specifically constipation and/or diarrhea. The diagnosis should be considered in patients with constipation who have associated abdominal pain (often relieved or aggravated by defecation). (See "Clinical manifestations and diagnosis of irritable bowel syndrome in adults".)
Chronic idiopathic constipation — Chronic idiopathic constipation can be diagnosed in patients who have at least three months of constipation symptoms without apparent secondary etiology and who do not meet criteria for IBS. Chronic idiopathic constipation can be due to defecatory dysfunction, slow transit constipation, or normal transit (ie, functional) constipation (table 2). Some patients have both defecatory dysfunction and slow or normal transit constipation.
In one study of 131 patients with chronic constipation evaluated at a tertiary care center, 47 percent had slow colonic transit, 59 percent had pelvic floor dysfunction, 58 percent had visceral hypersensitivity (indicative of IBS), and 24 percent had no physiologic abnormalities [22]. These results demonstrate the considerable overlap among these conditions. The etiologies of chronic idiopathic constipation are discussed in detail below in the order in which they are usually evaluated.
Defecatory dysfunction — Normal defecation requires the coordinated relaxation of the puborectalis and external anal sphincter muscles, together with increased intraabdominal pressure and inhibition of colonic segmenting activity. Defecation disorders result from the inability to coordinate the abdominal and pelvic floor muscles to evacuate stools. In adults, rectal evacuation disorders may be due to structural defects (eg, rectocele) or be functional in etiology (dyssynergic defecation or pelvic floor dyssynergia or functional outlet disorder) [23].
Patients with defecatory dysfunction often report excessive straining, prolonged defecation time, feelings of incomplete evacuation, and use of digital maneuvers to defecate (table 3). Digital rectal examination may demonstrate a high anal resting pressure, an impaired push effort, or a paradoxical contraction of the anal sphincter or puborectalis muscles during simulated evacuation [24].
The pathogenesis of dyssynergic defecation is not completely understood but is probably multifactorial. In patients with dyssynergic defecation, ineffective defecation is associated with a failure to relax, or inappropriate contraction of, the puborectalis and external anal sphincter muscles (figure 1) [25]. This narrows the anorectal angle and increases the pressures of the anal canal so that evacuation is less effective. It is thought to be an acquired, learned dysfunction rather than an organic or neurogenic disease. Relaxation of these muscles involves cortical inhibition of the spinal reflex during defecation; thus, this pattern may represent a conscious or unconscious act. (See "Fecal incontinence in adults: Etiology and evaluation", section on 'Normal defecation'.)
A diagnosis of dyssynergic defecation requires fulfillment of all the clinical criteria of functional constipation and the presence of consistent findings on anorectal manometry (ARM) and balloon expulsion testing (BET) (table 4). (See 'Anorectal manometry and balloon expulsion' below.)
Slow transit constipation — Patients with slow transit constipation often have long-standing constipation with consistently fewer than three bowel movements per week. The pathophysiology of slow transit constipation is incompletely understood. Patients have a resting colonic motility that is similar to normal controls, but they have little or no increase in motor activity after meals or with the administration of bisacodyl and a blunted response to cholinergic agents [26-28]. These findings suggest dysfunction in the enteric nerve plexus. Additionally, some colon specimens from patients with slow transit constipation who have had colon resections demonstrate a decreased volume of interstitial cells of Cajal in the myenteric plexus [29]. These cells are believed to play an important role in governing colonic motility.
Normal transit or functional constipation — The majority of patients with chronic idiopathic constipation have normal transit constipation. This is a disorder of gut-brain interaction and is also known as functional constipation or constipation without identifiable structural or biochemical cause.
The Rome IV criteria is the most accepted and widely used diagnostic criteria for functional constipation. The diagnosis is based on the presence of the following for at least three months (with symptom onset at least six months prior to diagnosis) [30].
●Must include two or more of the following:
•Straining during more than 25 percent of defecations.
•Lumpy or hard stools (Bristol Stool Scale Form 1 to 2) in more than 25 percent of defecations [31].
•Sensation of incomplete evacuation for more than 25 percent of defecations.
•Sensation of anorectal obstruction/blockage for more than 25 percent of defecations.
•Manual maneuvers to facilitate more than 25 percent of defecations (eg, digital evacuation, support of the pelvic floor).
•Fewer than three spontaneous bowel movements per week.
●Loose stools are rarely present without the use of laxatives.
●There are insufficient criteria for IBS. (See "Clinical manifestations and diagnosis of irritable bowel syndrome in adults".)
Although patients with functional constipation may have abdominal pain and/or bloating, these are not the predominant symptoms.
The pathogenesis of normal transit constipation is not well understood. Some patients with normal transit constipation demonstrate abnormalities of anorectal sensory and motor function that are indistinguishable from those in patients with slow transit constipation [32]. In addition, as with other disorders of gut-brain interaction, there may be a psychological aspect to normal transit constipation; patients with this condition exhibit increased psychosocial distress and may misperceive bowel frequency [32,33].
INITIAL EVALUATION
History and physical examination — The initial evaluation of patients with chronic constipation should include a careful history and physical examination to identify alarm features that warrant additional investigation (table 5) as well as secondary causes of constipation (algorithm 1). (See 'Secondary chronic constipation' above.)
●Assess for alarm features – Alarm features include the following:
•Hematochezia or heme-positive stool
•Iron deficiency anemia
•Unexplained weight loss of ≥10 pounds
•New onset of unexplained constipation
•New obstructive symptoms (eg, bloating, distension, abdominal pain during stool passage)
•Rectal pain or tenesmus
•Family history of colon cancer or inflammatory bowel disease
●Character of symptoms – This includes duration of symptoms, the frequency and characteristics of the stool, and associated symptoms. This may be aided by obtaining a two-week diary of symptoms, as many patients underestimate stool frequency without a stool diary [33]. The Bristol Stool Scale Form should be used to record stool consistency.
Symptoms that are suggestive of defecatory dysfunction include excessive straining, prolonged defecation time, feelings of incomplete evacuation, or use of digital maneuvers to defecate. (See 'Defecatory dysfunction' above.)
The presence of recurrent abdominal pain associated with periods of constipation is suggestive of irritable bowel syndrome (IBS). The evaluation of patients with IBS is discussed in detail separately. (See "Clinical manifestations and diagnosis of irritable bowel syndrome in adults", section on 'Overview of diagnostic approach'.)
●Medical history – As described above, several systemic and neurologic conditions are associated with constipation (table 1). Many patients already have an established diagnosis of one or more of these conditions, but in some cases, constipation may be the first symptom for which a patient seeks medical care. The history should include questions to elicit symptoms that could be consistent with these disorders (eg, weight gain and hair loss to evaluate for hypothyroidism).
●Medication use – The history should include exposure to medications that can cause constipation. The temporal relationship between starting the particular drug and onset of constipation should be elicited, particularly for medications that are uncommon causes of constipation (table 1).
●Family history – Assessment should include the presence of inflammatory bowel disease, colorectal cancer, and celiac disease.
●Physical examination – Physical examination including digital rectal examination is necessary to evaluate for abnormalities that could be causing constipation, particularly anorectal masses. A more detailed examination can help identify signs indicative of defecatory dysfunction.
•Abdominal examination – The abdominal examination should focus on palpation for masses. It is usually normal in patients with chronic constipation.
•Digital rectal examination – Specific components of the digital rectal examination in the evaluation of constipation include (table 6):
-Inspection – Identify skin rectal prolapse, anal fissures, or hemorrhoids.
-Palpation – Identify anorectal masses, strictures, or fecal impaction.
-Evaluation of resting anal tone – High resting anal tone (anismus) can be seen in dyssynergic defecation.
-Simulated evacuation – Evaluate anal relaxation and perineal descent during simulated evacuation. To do this, the patient is asked to push and bear down as if they are having a bowel movement. A normal response includes relaxation of the anal sphincter and puborectalis muscle, and descent of the perineum by 1 to 4 cm. Patients with dyssynergic defecation may have impaired push effort, or paradoxical contraction of the anal sphincter or puborectalis muscles.
The sensitivity of the digital rectal examination for identifying dyssynergic dysfunction is approximately 80 percent for experienced examiners [34-36]. However, sensitivity varies based on examiner experience. In a real-world study, the overall sensitivity of digital rectal examination for identifying dyssynergic dysfunction was 46 percent, ranging from 25 percent for nongastroenterology providers to 83 percent for gastroenterology attending physicians [36].
Signs of dyssynergia on rectal examination require confirmation on objective anorectal manometry (ARM) [37]. A normal rectal examination with no signs of dyssynergia generally rules out dyssynergic defecation. (See 'Anorectal manometry and balloon expulsion' below.)
Laboratory tests — We obtain laboratory testing to evaluate for secondary causes of constipation in most patients with constipation. This includes a complete blood cell count (to identify anemia), serum glucose or glycated hemoglobin (for diabetes mellitus), calcium (for hypercalcemia), potassium (for hypokalemia), and thyroid-stimulating hormone (for hypothyroidism). We also obtain serologic testing for celiac disease in those with risk factors (eg, family history). (See "Diagnosis of celiac disease in adults".)
Colonoscopy for patients with alarm features or age ≥45 years old — We perform a colonoscopy in patients with alarm features (table 5) and in patients age ≥45 years old presenting with constipation who have not previously had a colonoscopy (algorithm 1).
For patients age ≥45 years old without alarm symptoms, we favor at least a one-time colonoscopy for colon cancer evaluation; if normal, subsequent colon cancer screening can be completed either with colonoscopy or stool-based testing.
In patients < 45 years old without alarm symptoms who have had longstanding constipation, we do not recommend colonoscopy, especially if they have had a previous colonoscopy. This is consistent with guidelines from the American Gastroenterological Association (AGA) and American Society for Gastrointestinal Endoscopy (ASGE) [5,6].
Limited role for additional studies — No additional studies are routinely necessary in the initial evaluation of chronic constipation. However, additional studies may be helpful in selected patients.
●Abdominal computed tomography (CT) – Abdominal CT imaging may be necessary for further evaluation of patients with alarm symptoms (eg, a patient with abdominal pain and unintentional weight loss).
●Anorectal manometry (ARM) and balloon expulsion test (BET) – These tests are usually reserved for patients who do not respond to initial treatment measures, but they can be ordered as initial testing for patients in whom there is a high concern for dyssynergic defecation based on history or digital rectal examination.
●Plain radiographs of the abdomen – Plain films are not necessary in the routine evaluation of constipation, and a diagnosis of constipation should not be made based on a radiograph alone.
However, plain films may be helpful in the evaluation and follow-up of patients with constipation resistant to standard treatment and suspected fecal impaction. Plain films can detect significant stool retention in the colon and can help monitor bowel cleansing in these patients. They can also be useful in diagnosing megacolon or megarectum in the appropriate clinical context (eg, recurrent fecal impactions). However, these conditions are seen in only a small percentage of patients with constipation, and radiologic assessment does not always correlate with manometric evaluation [38,39].
THERAPEUTIC TRIAL OF LIFESTYLE MODIFICATION AND LAXATIVES —
Patients < 45 years old without alarm symptoms, and most patients ≥45 years old or with alarm symptoms who have a normal colonoscopy and routine laboratory results, can be managed with a therapeutic trial of lifestyle and diet modification and laxatives (algorithm 1). Specific counseling on lifestyle modification and selection of laxative agents are discussed in detail elsewhere. (See "Management of chronic constipation in adults", section on 'General approach'.)
For patients who have a secondary cause of constipation identified, treatment includes addressing the underlying cause when possible. In some cases, management of the underlying condition usually leads to resolution of constipation (eg, hypothyroidism, hypercalcemia), whereas in other cases, management of the underlying condition is less likely to improve constipation (eg, Parkinson disease, diabetes mellitus). When addressing the underlying etiology does not resolve constipation, we use the same management strategy as for chronic idiopathic constipation.
For patients on medications that are contributing to constipation, removal of the medications usually resolves the constipation, but this may not always be possible or advisable based on the underlying condition being treated. When a medication cannot be discontinued, our management is consistent with the approach for chronic idiopathic constipation. Additionally, for patients who have opioid-induced constipation, peripherally acting mu-opioid receptor antagonists may be helpful. (See "Prevention and management of side effects in patients receiving opioids for chronic pain", section on 'Constipation'.)
WHEN TO REFER —
Patients with alarm symptoms (table 5) and those ≥45 years old without a prior colonoscopy should be referred for colonoscopy, typically to a gastroenterologist. Patients who have a normal colonoscopy can be managed in either the primary care or specialty setting for medication initiation and titration.
In addition, gastroenterology evaluation can be helpful for patients in whom there is a high suspicion for defecatory dysfunction based on initial history and physical examination. Symptoms suggestive of defecatory dysfunction include excessive straining, prolonged defecation time, feelings of incomplete evacuation, and use of digital maneuvers to defecate. Findings on digital rectal examination that raise suspicion for defecatory dysfunction include a high anal resting pressure, an impaired push effort, or a paradoxical of the anal sphincter and puborectalis muscles during simulated evacuation. Defecatory dysfunction is diagnosed with anorectal manometry (ARM) and balloon expulsion test (BET), which is usually done in a gastroenterology office.
For patients without alarm symptoms, chronic idiopathic constipation can be evaluated and treated in the primary care setting, including initiation and titration of secretagogue agents if needed. (See "Management of chronic constipation in adults".)
SUBSEQUENT EVALUATION FOR PERSISTENT SYMPTOMS —
Patients with persistent symptoms despite treatment should undergo additional evaluation.
Assessment for a defecation disorder — Anorectal manometry (ARM) with balloon expulsion testing (BET) is the preferred initial test for defecatory dysfunction. Defecography is an alternative if initial testing is inconclusive.
Anorectal manometry and balloon expulsion — ARM with BET provides comprehensive information regarding the anal sphincter function at rest and during defecatory maneuvers; it is also able to identify reflex activation of the pelvic floor [39-41]. (See "Overview of gastrointestinal motility testing", section on 'Anorectal manometry'.)
●Technique – During ARM, a catheter with pressure sensors is inserted into the rectum. This permits measurement of anal sphincter pressure, rectal compliance and sensation, and the anorectal inhibitory reflex (ie, relaxation of the internal anal sphincter in response to distention of the rectum).
During BET, a balloon filled with warm tap water (typically 50 mL) is inserted into the rectum and must be expelled by the patient. Manometric readings during this simulated evacuation can help identify relaxation or inappropriate contraction of the external anal sphincter. The time required to expel the balloon is also assessed.
High-resolution manometry is generally preferred to conventional manometry, but there is no evidence that it is superior for clinical purposes.
●Interpretation – The characteristic normal pattern during expulsion of the manometer is an increase in intrarectal pressure and decrease in external sphincter pressure. In patients with dyssynergic defecation, there is an increase in external sphincter pressure during attempted expulsion of the manometer (figure 1). Manometric demonstration that the internal anal sphincter relaxes following rectal distension excludes Hirschsprung disease from diagnostic consideration.
For the BET, at most centers, the upper limit of normal to expel the balloon is one minute [42]. In one study of 286 patients with constipation, 38 percent passed the balloon within one minute, and 51 percent passed it within two minutes [43]. In contrast, among healthy controls, 93 percent expelled the balloon within one minute, and the remainder within two minutes.
Defecography — Defecography is a fluoroscopic imaging study that provides information about anatomic (eg, rectocele, enterocele, and intussusception) and functional (dyssynergic defecation) disorders of the anorectum.
●Indication – Defecography is indicated when results of an ARM and BET are inconclusive for a defecatory disorder [44].
●Technique – Defecography is performed by placing approximately 150 mL of thickened barium into the patient's rectum and having the patient squeeze, cough, and bear down. Evacuation of the barium can be monitored by fluoroscopy while the patient sits on a specially constructed commode.
●Interpretation – Assessment of the anorectal structures and the anorectal angle is made at rest and during expulsion of the barium mixture. Dyssynergic defecation is diagnosed by the presence of insufficient descent of the perineum (<1 cm) and less than a normal change in the anorectal angle (<15 degrees).
Magnetic resonance (MR) and dynamic MR defecography are alternatives to traditional barium defecography, although they are not widely available. These can evaluate global pelvic floor anatomy and sphincter morphology and assess dynamic motion, thereby providing valuable information without ionizing radiation. However, some studies have reported a high rate of nondiagnostic studies in patients undergoing MR defecography due to deficient straining and evacuation [45,46].
Assessment of colonic transit — Patients with persistent constipation who do not have evidence of a defecation disorder should undergo further testing to identify slow colonic transit.
Radiopaque marker study — The radiopaque marker study is the preferred test to assess colonic transit (See "Overview of gastrointestinal motility testing", section on 'Radiopaque marker study'.).
•Description – The patient ingests radiopaque markers (usually 24 markers in a single capsule) that can be monitored with radiographs as they move through the colon. In routine clinical use, a single radiograph is taken on day 6 to identify the number and location of markers remaining in the gastrointestinal tract.
•Interpretation – Retention of more than five markers on day 6 is considered abnormal and indicative of slow transit constipation.
It is important to note that patients with defecatory disorder may also have marker retention; a purported pattern seen in defecatory dysfunction is normal marker progression through the proximal colon with stagnation in the rectum [23,47-49]. However, these findings have not been validated for and do not always correlate with defecatory dysfunction [50,51]. The only accurate test for defecatory dysfunction is the ARM with BET.
Other tests — Several additional tests can help evaluate colonic transit, but these are used less frequently than the radiopaque marker study, largely due to limited availability.
●Wireless motility capsule (WMC) – The WMC can assess regional (gastric emptying, small bowel transit, and colonic transit) and whole gut transit times. (See "Overview of gastrointestinal motility testing", section on 'Wireless motility capsule'.)
The sensitivity and specificity are similar with those of radiopaque marker tests and scintigraphic gastric emptying [52]. The WMC has been validated against the radiopaque marker test in patients with chronic constipation [53,54]. WMC is well tolerated, has good compliance, and avoids the risks of radiation exposure. However, it is more expensive than the radiopaque marker study, and it is not clear that it provides added clinical value in most patients. It is no longer available in the United States.
●Scintigraphy – Scintigraphy uses a gamma-camera to assess the passage of a radioisotope (111In or 99Tc), administered either in a coated capsule that dissolves in the colon or terminal ileum or a nondigestible capsule administered with a test meal. The results are a weighted distribution of the radioisotope in the colon at 24 hours and, if necessary, at 48 hours. In patients with dyssynergic defecation, there is delayed overall colonic transit at 48 hours and ascending colon half-emptying time. Regional scintigraphic transit profiles do not adequately differentiate dyssynergic defecation from slow transit constipation [55]. Both radiopaque markers and scintigraphy provide a quantitative assessment of colonic transit and are considered equivalent [56,57]. However, scintigraphy is not as widely available.
SOCIETY GUIDELINE LINKS —
Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Constipation".)
INFORMATION FOR PATIENTS —
UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)
●Basics topics (see "Patient education: Constipation in adults (The Basics)")
●Beyond the Basics topics (see "Patient education: Constipation in adults (Beyond the Basics)")
SUMMARY AND RECOMMENDATIONS
●Prevalence – The prevalence of chronic constipation ranges from 12 to 19 percent, with higher rates in females compared with males. The prevalence of chronic constipation increases with age, most dramatically in patients 65 years of age or older. (See 'Epidemiology and risk factors' above.)
●Etiology – Constipation commonly occurs secondary to other health conditions (eg, metabolic or neurologic disorders, obstructing lesions of the gastrointestinal tract) or as a side effect of medications (table 1). Irritable bowel syndrome (IBS), another common etiology of constipation, is characterized by the presence of recurrent abdominal pain associated with periods of constipation, diarrhea, or normal bowel function. Individuals with chronic idiopathic constipation may have defecatory dysfunction, slow transit constipation, or normal transit constipation (ie, functional constipation). (See 'Etiology and pathogenesis' above.)
●Evaluation – The initial evaluation of patients who present with chronic constipation includes a history, physical examination, and laboratory studies to identify secondary causes of constipation and alarm features that warrant additional evaluation for organic disease (algorithm 1). (See 'Initial evaluation' above.)
Alarm features include the following:
•Hematochezia or heme-positive stool
•Iron deficiency anemia
•Unexplained weight loss ≥10 pounds
•New onset of unexplained constipation
•New obstructive symptoms (eg, bloating, distension, abdominal pain during stool passage)
•Rectal pain or tenesmus
•Family history of colorectal cancer or inflammatory bowel disease
●Colonoscopy for patients with alarm features or age ≥45 years old – We perform a colonoscopy in patients with alarm features and in patients aged ≥45 years old with constipation who have not previously had a colonoscopy to exclude organic disease. We do not advise colonoscopy in younger patients without alarm symptoms (See 'Colonoscopy for patients with alarm features or age ≥45 years old' above.)
●Considerations for specialty referral – Patients with alarm symptoms (table 5) and those age ≥45 years old without a prior colonoscopy should be referred for colonoscopy, typically to a gastroenterologist. Patients who have a normal colonoscopy can be managed in either the primary care or specialty setting for medication initiation and titration. In addition, gastroenterology evaluation can be helpful for patients in whom there is a high suspicion for defecatory dysfunction based on initial history and physical examination; confirmatory testing is usually done through a gastroenterologist. (See 'When to refer' above.)
●Patients with persistent symptoms despite a trial of fiber and laxatives – Most patients with persistent symptoms despite a trial of fiber and laxatives undergo evaluation for an underlying defecatory disorder with anorectal manometry (ARM) and balloon expulsion test (BET). Defecography should be performed when results of ARM and BET are inconclusive for a defecatory disorder. Patients without evidence of a defecatory disorder who have persistent constipation should undergo an assessment of colonic transit to identify slow transit constipation. (See 'Subsequent evaluation for persistent symptoms' above.)
